#1- Delete the old name and setup new name
sudo hostnamectl set-hostname newHostname
#2- Edit the /etc/hosts file:
sudo nano /etc/hosts
#3- Reboot the system
sudo reboot
#4- To check the new hostname
hostnamectlsudo nano /etc/hostname
sudo nano /etc/hosts
sudo reboot# -l changes login name
# -d changes home directory
# -m copies over contents from old home directory
usermod -l <newname> -d /home/<newname> -m <oldname>
# NOTE: will not work if you are currently logged on as user
# - workaround by temporarily enabling root account and running above command there
# [sudo passwd root]
# - after root account has been used to change username lock it using
# [sudo passwd -l root]